Wave Optics

In Young's double slit experiment, the intensity at a point where path difference is \(\frac{\lambda}{6}\) (\(\lambda\) being the wavelength of light used) is \(I^{\prime}\). If '\(I_0\)' denotes the maximum intensity, then \(\frac{I}{I_0}\) is equal to \(\left(\cos 0^{\circ}=1, \cos 60^{\circ}=\frac{1}{\lambda}\right)\)